1 //===-- FifoFiles.cpp -------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "FifoFiles.h"
10
11 #if !defined(_WIN32)
12 #include <sys/stat.h>
13 #include <sys/types.h>
14 #include <unistd.h>
15 #endif
16
17 #include <chrono>
18 #include <fstream>
19 #include <future>
20 #include <optional>
21 #include <thread>
22
23 #include "llvm/Support/FileSystem.h"
24
25 #include "lldb/lldb-defines.h"
26
27 using namespace llvm;
28
29 namespace lldb_vscode {
30
FifoFile(StringRef path)31 FifoFile::FifoFile(StringRef path) : m_path(path) {}
32
~FifoFile()33 FifoFile::~FifoFile() {
34 #if !defined(_WIN32)
35 unlink(m_path.c_str());
36 #endif
37 }
38
CreateFifoFile(StringRef path)39 Expected<std::shared_ptr<FifoFile>> CreateFifoFile(StringRef path) {
40 #if defined(_WIN32)
41 return createStringError(inconvertibleErrorCode(), "Unimplemented");
42 #else
43 if (int err = mkfifo(path.data(), 0600))
44 return createStringError(std::error_code(err, std::generic_category()),
45 "Couldn't create fifo file: %s", path.data());
46 return std::make_shared<FifoFile>(path);
47 #endif
48 }
49
FifoFileIO(StringRef fifo_file,StringRef other_endpoint_name)50 FifoFileIO::FifoFileIO(StringRef fifo_file, StringRef other_endpoint_name)
51 : m_fifo_file(fifo_file), m_other_endpoint_name(other_endpoint_name) {}
52
ReadJSON(std::chrono::milliseconds timeout)53 Expected<json::Value> FifoFileIO::ReadJSON(std::chrono::milliseconds timeout) {
54 // We use a pointer for this future, because otherwise its normal destructor
55 // would wait for the getline to end, rendering the timeout useless.
56 std::optional<std::string> line;
57 std::future<void> *future =
58 new std::future<void>(std::async(std::launch::async, [&]() {
59 std::ifstream reader(m_fifo_file, std::ifstream::in);
60 std::string buffer;
61 std::getline(reader, buffer);
62 if (!buffer.empty())
63 line = buffer;
64 }));
65 if (future->wait_for(timeout) == std::future_status::timeout || !line)
66 // Indeed this is a leak, but it's intentional. "future" obj destructor
67 // will block on waiting for the worker thread to join. And the worker
68 // thread might be stuck in blocking I/O. Intentionally leaking the obj
69 // as a hack to avoid blocking main thread, and adding annotation to
70 // supress static code inspection warnings
71
72 // coverity[leaked_storage]
73 return createStringError(inconvertibleErrorCode(),
74 "Timed out trying to get messages from the " +
75 m_other_endpoint_name);
76 delete future;
77 return json::parse(*line);
78 }
79
SendJSON(const json::Value & json,std::chrono::milliseconds timeout)80 Error FifoFileIO::SendJSON(const json::Value &json,
81 std::chrono::milliseconds timeout) {
82 bool done = false;
83 std::future<void> *future =
84 new std::future<void>(std::async(std::launch::async, [&]() {
85 std::ofstream writer(m_fifo_file, std::ofstream::out);
86 writer << JSONToString(json) << std::endl;
87 done = true;
88 }));
89 if (future->wait_for(timeout) == std::future_status::timeout || !done) {
90 // Indeed this is a leak, but it's intentional. "future" obj destructor will
91 // block on waiting for the worker thread to join. And the worker thread
92 // might be stuck in blocking I/O. Intentionally leaking the obj as a hack
93 // to avoid blocking main thread, and adding annotation to supress static
94 // code inspection warnings"
95
96 // coverity[leaked_storage]
97 return createStringError(inconvertibleErrorCode(),
98 "Timed out trying to send messages to the " +
99 m_other_endpoint_name);
100 }
101 delete future;
102 return Error::success();
103 }
104
105 } // namespace lldb_vscode
106